The regulation of electrical power delivered to a load such as a lamp has been proposed and accomplished heretofore. Depending upon the nature and characteristics of the particular load involved, such regulation has been directed to controlling levels of illumination from lamps, speeds of motors, temperatures of electrical heaters, and other such characteristic operations. As the technology associated with such control over electrical power has developed, various types of apparatus have been proposed and used to accomplish such control.
In many instances, the range of usefulness of particular controls is limited by interactions between the electrical load and the control. Further, it is recognized as being desirable to avoid loss of electrical power in the apparatus employed to control the load.
Achievement of these objectives has not always been available or possible. By way of example only, early controls reliant upon varying resistance directly satisfactorily accomplished control over certain types of electrical loads such as incandescent lamps but resulted in relatively great losses. More recently developed technology, using semiconductor switches, avoids the loss realized by some early control apparatus but often times is limited to specific environments of use and are not widely applicable to a number of different types of electrical loads.